Coupling of Rigor Mortis and Intestinal Necrosis during C. elegans Organismal Death

Organismal death is a process of systemic collapse whose mechanisms are less well understood than those of cell death. We previously reported that death in C. elegans is accompanied by a calcium-propagated wave of intestinal necrosis, marked by a wave of blue autofluorescence (death fluorescence). Here, we describe another feature of organismal death, a wave of body wall muscle contraction, or death contraction (DC). This phenomenon is accompanied by a wave of intramuscular Ca ²⁺ release and, subsequently, of intestinal necrosis. Correlation of directions of the DC and intestinal necrosis waves implies coupling of these death processes. Long-lived insulin/IGF-1-signaling mutants show reduced DC and delayed intestinal necrosis, suggesting possible resistance to organismal death. DC resembles mammalian rigor mortis, a postmortem necrosis-related process in which Ca ²⁺ influx promotes muscle hyper-contraction. In contrast to mammals, DC is an early rather than a late event in C. elegans organismal death. Video Abstract [Figure presented] Galimov et al. describe mechanisms of organismal death in C. elegans. They document a rigor mortis-like wave of muscle hyper-contraction accompanied by Ca ²⁺ release and falling ATP, which is coupled to the previously described wave of intestinal necrosis in a process that resembles a distorted and deadly defecation cycle.